Anyone know how many there are? What's the best one?

http://fallout.wikia.com/wiki/Fallout:_New_Vegas_locations#Mojave_Wasteland_unmarked_individual_locations

I don't know if that's all, but it's quite something.

For me Camp Guardian caves were the most interesting in my 1st playthrough especially if you pick up and read various notes you find on your way to the camp.

I heard about one by Quarry Junction...Meridians I think?